------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 24024 at lib/refcount.c:25 refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 24024 Comm: syz-executor.5 Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25
Code: c7 e0 d4 b3 8a 31 c0 e8 01 1d 3d fd 0f 0b eb a3 e8 68 e7 71 fd c6 05 85 1a b8 09 01 48 c7 c7 40 d5 b3 8a 31 c0 e8 e3 1c 3d fd <0f> 0b eb 85 e8 4a e7 71 fd c6 05 68 1a b8 09 01 48 c7 c7 a0 d5 b3
RSP: 0018:ffffc90009f57788 EFLAGS: 00010246
RAX: 05764e183f445000 RBX: 0000000000000002 RCX: ffff888087a41c80
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffffffff81682012 R09: ffffed10173857a8
R10: ffffed10173857a8 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880754ea968 R14: ffff888070362200 R15: 0000000000000067
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f75cd093100 CR3: 000000003ea64000 CR4: 00000000001506f0
Call Trace:
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sock_hold include/net/sock.h:702 [inline]
 sco_conn_del+0x242/0x2f0 net/bluetooth/sco.c:193
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
 hci_conn_hash_flush+0x112/0x240 net/bluetooth/hci_conn.c:1608
 hci_dev_do_close+0x93e/0xeb0 net/bluetooth/hci_core.c:1793
 hci_unregister_dev+0x2a2/0x510 net/bluetooth/hci_core.c:4029
 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x3fe/0x870 fs/file_table.c:280
 task_work_run+0x146/0x1c0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x6fc/0x2580 kernel/exit.c:825
 do_group_exit+0x168/0x2d0 kernel/exit.c:922
 get_signal+0x16e0/0x20c0 kernel/signal.c:2868
 arch_do_signal_or_restart+0x9c/0x730 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x191/0x220 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:302
 do_syscall_64+0x53/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f7ad2db9739
Code: Unable to access opcode bytes at RIP 0x7f7ad2db970f.
RSP: 002b:00007f7ad026a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffed RBX: 00007f7ad2ebe3d0 RCX: 00007f7ad2db9739
RDX: 0000000020000080 RSI: 0000000000008918 RDI: 0000000000000004
RBP: 00007f7ad2e13cc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7ad2ebe3d0
R13: 00007ffecd2622ef R14: 00007f7ad026a300 R15: 0000000000022000